I suppose the WORST they could do to you is sue you for using the vehicle outside of contract limits...
The most likely thing is they will do, is exactly what the contract states for violating the contract.... You will immediately Void the contract and have to return the vehicle.
If the rentals goes uneventful, there will not be an issue.
If it all goes unbelievably, horribly wrong, you may be refused rentals with them in the future.
Insurance covers all all forms of stupid actions. Just don't let your Surburban Totaling Son drive it.
As long as a major felony involving prison time is not in the equation, you should be OK.
If you enter a Rock Climbing competition and roll it down a cliff, you may have some explaining to do.
